With the help of Steven, we have done the array deserilaztion with policy.
https://github.com/schveiguy/jsoniopipe/pull/44
https://github.com/schveiguy/jsoniopipe/pull/43

Then I refactored function names and removed legacy code to align policy-based deserialization with the current API.
https://github.com/schveiguy/jsoniopipe/pull/47

At last, Steven thinks deserializeItem dispatch is probably a wrong appoach, because it relys on __traits(compiles) which may deafen some errors. We will try a new way.
https://github.com/schveiguy/jsoniopipe/issues/45#issuecomment-3121018744